The efficient use of coal has attracted attention as one of trumps to solve a recent energy problem.
On the other hand, it is necessary to have an advanced technique such as a coal gasifying technique and a gas purifying technique in order to convert the coal as an energy medium with high added value.
An integrated coal gasification combined power generation system which generates power by using the gasified gas has been proposed (Patent Literature 1).
The integrated coal gasification combined power generation (Integrated coal Gasification Combined Cycle: IGCC) is a system for converting the coal into combustible gas by a high-temperature high-pressure gasification furnace and performing combined power generation by a gas turbine and a steam turbine using the gasified gas as a fuel.
For example, most of hydrocarbon compounds existing in coal gasified gas (produced gas) are carbon monoxide (CO), and carbon dioxide (CO2) and hydrocarbon (CH4 and CnHm) only account for a few percent. As a result, it is necessary to convert CO existing in the produced gas into CO2 in order to recover CO2. It has been proposed to convert CO into CO2 by the following reaction by using the CO shift catalyst while adding water vapor (H2O) (Patent Literature 2).CO+H2O⇔CO2+H2+40.9 kJ/mol (exothermic reaction)   (1)
According to the knowledge to relative to the shift reaction in the field of chemical industry before, by sufficiently increasing a water vapor adding ratio (H2O/CO) at a CO shift reactor inlet, the above-mentioned reaction of (1) is proceeded, and a desired CO→CO2 conversion rate can be obtained.